Histochemistry and storage of organic compounds during basidiosporogenesis in the ectomycorrhizal fungus Pisolithus microcarpus

Abstract

Knowledge on the distribution and storage of different organic compounds during basidiosporogenesis in P. microcarpus is paramount to a better understanding of basidiospore recalcitrance to germination. The objective of this work was to detect the presence and distribution of phenolics, reducing sugars, starch, glycogen, total polysaccharides, RNA, and proteins during P. microcarpus basidiosporogenesis. Starch and reducing sugars were not detected in the fungal basidiocarps, while other polysaccharides predominated in the extracellular matrix at the base of the basidiocarp containing unconsolidated peridioles. Phenolics were also detected in this region. Glycogen was present inside the hyphae, basidia, and basidiospores and constitutes an important storage compound in the fungal basidiocarps. In mature basidiospores, RNA accumulation occurred at discrete locations in the cytoplasmatic periphery, while polysaccharides and proteins were shown to predominate in the cell wall. The presence of glycogen, RNA, and proteins inside the basidiospores strongly indicates provision for future germination and suggests that other factors may also influence basidiospore recalcitrance.

Dicer-Like Proteins Regulate Sexual Development via the Biogenesis of Perithecium-Specific MicroRNAs in a Plant Pathogenic Fungus Fusarium graminearum

“…In F. graminearum , the turgor pressure of asci is necessary for ascospore discharge, and ion fluxes and sugar alcohol accumulation are related to the generation of turgor pressure, especially in K + , Na + , Cl - and Ca ++ ion channels ( Trail et al, 2002 , 2005 ; Min et al, 2010 ). Indeed, this process may contribute to the up-regulated DEGs in sodium ion transmembrane transporter activity, solute: cation symporter activity, and the decrease in glycogen accumulation by glycogen staining ( Figure 3C and Supplementary Figures S3A , S5 ; da R Campos and Costa, 2010 ).…”

“…After induction for 7 days induction, perithecia and asci were observed under dissecting and light microscopes, respectively. The glycogen staining of asci was performed as previously reported ( da R Campos and Costa, 2010 ). Ascospore discharge was detected in a coverslip and place in a closed box.…”

Basidiosporogenesis, meiosis, and post-meiotic mitosis in the ectomycorrhizal fungus Pisolithus microcarpus

“…2a). The abundance of the gelatinous matrix decreases as the basidiospores go through more advanced developmental stages and has been shown to be composed mainly by polysaccharides (Campos and Costa, 2010). The gelatinous matrix is also commonly found in the basidiocarps of other gasteromycetal species and is probably derived from the lyses of hyphae inside the peridioles (Mims, 1980;Moore-Landecker, 1996).…”

“…4). The fact that all spores are nucleate and contain large quantities of storage compounds (Mims, 1980;Campos et al, 2008;Campos and Costa, 2010) indicates the provision of carbon and organelles to direct basidiospore germination and initial vegetative growth in the host plant rhizosphere. This is the first report on meiosis and post-meiotic mitosis in a fungal species within the genus Pisolithus and contributes to a better understanding of fungal biology and reproduction.…”

“…Knowledge on basidiospore formation, such as the concurrent deposition of spore cell wall layers and storage of reserve compounds have been described for a few Pisolithus species, indicating provision for future spore germination (Mims, 1980;Campos et al, 2008;Campos and Costa, 2010). The early steps of basidiospore formation in Pisolithus tinctorius (Pers.)…”